Optical inspection tools are used to inspect targets, such as semiconductor wafers, by providing an optical beam, which is also referred to as an illumination beam, that scatters off of the target. The presence of a defect, such as a particle, on the surface of the target within a track illuminated by the optical beam (i.e., within an “inspection track”) will affect how the optical beam is scattered, thus allowing detection of the defect. The shape of the optical beam, however, limits the sensitivity of the optical inspection tool. For example, if the optical beam is approximately Gaussian, such that the intensity falls off toward the edges of the inspection track, then this intensity fall-off limits the sensitivity threshold used to detect defects within the track. Alternatively, the beam intensity for the optical tool may have to be increased to achieve the desired sensitivity. Furthermore, the optical beam may have an oblique angle of incidence with the target, such that the angle of incidence is not a right angle (i.e., the optical beam is incident on the target at a slant). When the angle of incidence is oblique, the shape of the optical beam in the plane of the target will differ from the shape of the optical beam in a radial plane.